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Variable Stars in Terzan 5: Additional Evidence of Multi-age and Multi-iron Stellar Populations
Dalessandro, E.; Massari, D.; Contreras Ramos, R. +7 more
Terzan 5 is a complex stellar system in the Galactic bulge, harboring stellar populations (SPs) with very different iron content (Δ[Fe/H] ∼ 1 dex) and with ages differing by several gigayears. Here we present an investigation of its variable stars. We report on the discovery and characterization of three RR Lyrae stars. For these newly discovered …
Characterizing circumgalactic gas around massive ellipticals at z ≈ 0.4 - III. The galactic environment of a chemically pristine Lyman limit absorber
Bouché, Nicolas; Johnson, Sean D.; Marino, Raffaella Anna +7 more
This paper presents a study of the galactic environment of a chemically pristine (<0.6 per cent solar metallicity) Lyman Limit system (LLS) discovered along the sightline towards QSO SDSSJ 135726.27+043541.4 (zQSO = 1.233) at projected distance d = 126 physical kpc (pkpc) from a luminous red galaxy (LRG) at z = 0.33. Combining deep H…
Investigations of a supra-arcade fan and termination shock above the top of the flare-loop system of the 2017 September 10 event
Lin, Jun; Raymond, John C.; Roussev, Ilia I. +4 more
On 2017 September 10, a major eruption on the west solar limb produced a class X-8.2 flare and a superfast coronal mass ejection (CME). During the eruptive process, the geometric topology of the erupting magnetic configuration presented a clear flare-current sheet (CS)-CME structure. Analysing the images and spectral data from the Solar Dynamics O…
The Population of Pulsating Variable Stars in the Sextans Dwarf Spheroidal Galaxy
Mateo, Mario; Vivas, A. Katherina; Alonso-García, Javier +2 more
A large extension of the Sextans dwarf spheroidal galaxy, 7 deg2, has been surveyed for variable stars using the Dark Energy Camera at the Blanco Telescope at Cerro Tololo Inter-American Observatory, Chile. We report seven anomalous Cepheids, 199 RR Lyrae stars, and 16 dwarf Cepheids in the field. This is only the fifth extragalactic sy…
Measuring the filamentary structure of interstellar clouds through wavelets
Ossenkopf-Okada, V.; Stepanov, R.
Context. The ubiquitous presence of filamentary structures in the interstellar medium asks for an unbiased characterization of their properties including a stability analysis.
Aims: We propose a novel technique to measure the spectrum of filaments in any two-dimensional data set. By comparing the power in isotropic and anisotropic structures …
The Origin of the Late-time Luminosity of Supernova 2011dh
Maund, Justyn R.
Due to the small amount of hydrogen (≤0.1 M ⊙) remaining on the surface of their progenitors, SNe IIb are sensitive probes of the mass-loss processes of massive stars toward the ends of their lives, including the role of binarity. We report late-time Hubble Space Telescope observations of SN 2011dh in M51, and a brief period of rebright…
Spectroscopic membership for the populous 300 Myr-old open cluster NGC 3532
Strassmeier, K. G.; Barnes, S. A.; James, D. J. +3 more
Context. NGC 3532 is an extremely rich open cluster embedded in the Galactic disc, hitherto lacking a comprehensive, documented membership list.
Aims: We provide membership probabilities from new radial velocity observations of solar-type and low-mass stars in NGC 3532, in part as a prelude to a subsequent study of stellar rotation in the clu…
A Trio of Massive Black Holes Caught in the Act of Merging
Shen, Yue; Nyland, Kristina; Li, Zhiyuan +6 more
We report the discovery of SDSS J0849+1114 as the first known triple Type 2 Seyfert nucleus. It represents three active black holes that are identified from new spatially resolved optical slit spectroscopy using the Dual Imaging Spectrograph on the 3.5 m telescope at the Apache Point Observatory. We also present new complementary observations incl…
Direct detection of quasar feedback via the Sunyaev-Zeldovich effect
Nyland, Kristina; Lacy, Mark; Surace, Jason +6 more
The nature and energetics of feedback from thermal winds in quasars can be constrained via observations of the Sunyaev-Zeldovich Effect (SZE) induced by the bubble of thermal plasma blown into the intergalactic medium by the quasar wind. In this letter, we present evidence that we have made the first detection of such a bubble, associated with the…
RELICS: High-resolution Constraints on the Inner Mass Distribution of the z = 0.83 Merging Cluster RXJ0152.7-1357 from Strong Lensing
Ouchi, Masami; Mahler, Guillaume; Bradač, Maruša +37 more
Strong gravitational lensing (SL) is a powerful means of mapping the distribution of dark matter. In this work, we perform an SL analysis of the prominent X-ray cluster RXJ0152.7-1357 (z = 0.83, also known as CL0152.7-1357) in Hubble Space Telescope images, taken in the framework of the Reionization Lensing Cluster Survey (RELICS). On top of a pre…